Apparatus for crimping electrical terminals and tensile test apparatus for testing the crimped connection



Oct. 21, 1969 l. G. 0. BROWN 3,473,213

APPARATUS FOR CRIMPING ELECTRICAL TERMINALS AND TENSILE TEST APPARATUS FOR TESTING THE CRIMPED CONNECTION Original Filed March 10, 1966 (III: 38

' INVENTOR.

WAN Goumn OLWER Bawn BY KW Uted States Patent 3,473,213 APPARATUS FGR ClRiMPlNG ELECTRKCAL TER- MZNALS AND TENSIELE TEST APPARATUS FOR TESTlNG THE CRIMPED CONNECTION Ivan Godfrey (lliver Brown, Southdown, Penshurst, England, assignor to AMP Incorporated, Harrisburg, Pa. Continuation of abandoned application Ser. No. 533,327, Mar. 10, 1966. This application Aug. 13, 1968, Ser. No. 7 67,013 Claims priority, appiication Great Britain, Mar. 13, 1965, 10,745/ 65 int. Cl. B231) 11/00; B2311 17/00 US. Cl. 29-203 Claims ABSTRACT OF THE DISCLGSURE This application is a continuation of application Ser. No. 533,327, filed Mar. 10, 1966, now abandoned.

The present invention relates to an apparatus for crimping an electrical connector element onto a bared conductor wire and for automatically testing the tensile strength of the crimped connection.

It is common practice to form electrical connections by crimping or compressing electrical connectors to conductor wires with an automatic or semi-automatic crimping or compressing apparatus. Since such apparatus may produce imperfect connections if the crimping dies are maladjusted or the electrical connectors themselves are bent or otherwise defective, it is usual to test connections made by the apparatus for tensile strength. These tests are normally made with the aid of a testing device, which is usually bench-mounted, for applying a predetermined test force, for example, of lbs. (approximately 4.5 kilograms) tending to separate the conductor wire and the electrical connector. In the interests of economy, the crimping apparatus may be run at a speed of at least 1,500 crimping operations per hour; it is therefore practicable to test but a very small fraction of the completed connections.

According to the present invention, an apparatus for performing a crimping operation to form an electrical connection between an electrical connector and a conductor wire and for automatically testing the tensile strength of the connection, comprises a connector crimping device, a mechanism actuable by operation of the crimping device to grip the wire when positioned in the connector and to subsequently apply to the crimping operation a force tending to separate the connector and the conductor wire, and means for causing the mechanism to release the Wire when the force applied reaches a predetermined test value. The mechanism for gripping the conductor wire comprises a pair of wire gripper jaws which are moved away from a connector crimping station of the crimping device at a given instant after the crimping or compressing operation has been completed, and relative to a stop for the crimped connector, the stop being disposed between the wire gripper jaws and the crimping station, to apply the force. The stop may be movable by abutment with the connector against a predetermined force against 3,473,2l3 Patented Oct. 21, 1969 the action of a piston in a fluid containing cylinder or of a spring, to cause the wire gripper jaws to release the conductor wire. The said jaws may be arranged to continue their movement in the event the wire and the connector are separated from one another by the movement of the jaws in order to actuate means for suspending the operation of the crimping device. The stop may be formed by a rotatably mounted member having on one side of its axis of rotation a slot through which the conductor wire extends when positioned relative to the connector for crimping, the member having on the other side of the axis a portion normally engaging an abutment movable by the member against the predetermined force for causing the jaws to release the wire via a switch.

The wire gripper jaws may be arranged to be closed about the wire by a switch for initiating a working cycle of the crimping device and may conveniently be operated by a piston engageable with cam surfaces on the jaws to open and close the jaws.

It is therefore an object of the present invention to provide an apparatus for crimping electrical connector elements onto a bared conductor wire.

It is an additional object to provide an apparatus for automatically testing the tensile strength of the crimped connection.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of the invention; it is to be understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention but is given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

In the drawings:

FIGURE 1 is a diagram partly in schematic form and illustrating part of a machine for crimping electrical connectors to wires and mechanism associated with the machine for testing the tensile strength of the electrical connections made thereby; and

FIGURE 2 is a view taken along the lines 2-2 of FIGURE 1.

The machine comprises a press bed 2 including a crimping anvil 4 having a working face on which is disposed an essentially U-section crimping ferrule 6 of an electrical connector element comprising a ring-tongue 8 which is integrally formed with the ferrule 6, the bight of the U lying adjacent the crimping anvil 4. This connector forms part of a strip of identical connectors joined together by metal slugs 10. A movable crimping die 12 is arranged to be driven in reciprocation towards and away from the crimping anvil 4 by a press ram (not shown) in response to the actuation of a starting foot switch (not shown) e.g. a pedal switch. A feed finger 14 reciprocable longitudinally of the strip of electrical connectors, for example, by the press ram, is arranged to advance the strip towards the crimping anvil 4 to locate the leading electrical connector of the strip on the working surface after each crimping operation. During the crimping operation the slug 10 is sheared from between the leading electrical connector and the next following electrical connector of the strip by shear means (not shown).

A connector stop member 16 is pivotable about an axis 18 relative to a support plate 20 fixed beneath the press bed 2. The stop member 16 is bifurcated at its upper (as seen in FIGURE 1) end to define a slot 22 opening into the upper surface of the said stop member 16. The width of this slot is less than the diameter of the ferrule 6 so that the ferrule cannot pass through the slot. The lower (as seen in FIGURE 1) end 17 of the stop member 16 extends between the free end of a piston rod 24 and the switch button 19 of a switch 26. This lower end 17 is normally in engagement both with the free end of the piston rod and with the switch button and maintains the switch button 19 in a depressed condition. The piston rod 24 is connected to a piston (not shown) in a pneumatic cylinder 28, the said piston rod 24 being movable to the left (as seen in FIGURE 1) against the action of constant predetermined pneumatic load.

A pair of wire gripper jaws 30 having serrated working ends are pivotable about pins 38 from an open position (best seen in FIGURE 2) towards a closed position by the cam shaped head 32 of a piston rod, movable between cam followers 34 (only one of which is shown) on the wire gripper jaws 30, and extending from a piston (not shown) in a pneumatic cylinder 36. This piston is arranged to be advanced when the starting switch (the foot switch referred to above) is actuated to close the wire gripper jaws against the action of a spring (not shown), and to be retracted to open the said jaws 30 when the switch 26 is actuated (i.e. when the switch button is permitted to move leftwardly from its depressed condition). The pneumatic cylinder 36 is mounted on a cradle 40 pivotable about an axis 42 through a linkage 44 under the action of a pneumatic motor 46 to move the wire gripper jaws 30 towards and away from the stop member 16, between an initial position (FIGURE 1) in which the cradle 40 actuates a switch 48 and a second position in which the cradle 40 actuates a switch 50. When actuated the switch 48 causes a machine in order indication to be displayed, e.g. a green lamp (not shown) to be illuminated. The switch 50 when actuated breaks the circuit of the starting switch so that the machine cannot be operated, and may also cause a warning indication to be displayed, e.g. a red lamp (not shown) to be illuminated. The pneumatic motor 46 is operated, e.g. by a switch (not shown) to drive the cradle 40 when the feed finger 14 reaches a predetermined position to the right of that in which the feed finger 14 is shown in FIG- URE 1. The cradle 40 is arranged to be returned to its initial position when the switch 26 is actuated.

At the beginning of a cycle of operation of the machine the ram is in its top dead center position, the crimping die 12, feed finger 14, stop member 16 and cradle 40 are positioned as shown in FIGURE 1 and the wire gripper jaws 30 are open as shown in FIGURE 2. The end of a wire W is laid in the crimping ferrule 6 of the leading electrical connector as shown in FIGURE 1 so that the wire extends between the working ends of the wire gripper jaws 30 and through the slot 22. The starting switch of the machine is now operated to cause the ram and thus the crimping die 12 to be driven through a working cycle, and simultaneously to cause the piston in the pneumatic cylinder 36 to advance to cause the wire gripper jaws 30 to close about the wire W. The crimping die 12 is initially moved through a working stroke and cooperates with the crimping anvil 4 to crimp the ferrule 6 to the wire W during the working stroke, the slug being sheared out by the shear means to free the leading electrical connector from the strip. The ram now drives the crimping die 12 through a return stroke and simultaneously causes the feed finger 14 to move to the right (as seen in FIGURE 1) to advance the next following electrical connector of the strip onto the working surface of the crimping anvil 4. When the feed finger 14 reaches its predetermined rightward position, the cradle 40' is driven in its clockwise sense of rotation about the axis 42 to cause the wire gripper jaws 30 between which the wire W is gripped, to move away from the crimping anvil 4, to pull the electrical connector which has been crimped to the wire W against the upper end of the stop member 16. If the tensile strength of the crimped connection between the crimping ferrule 6 and wire'W exceeds a value, e.g. 10 lbs. (approximately 4.5 kilograms) predetermined by the load against which the piston rod 24 is displaceable, the said piston rod 24 is moved to the left (as seen in FIGURE 1) so that the stop member 16 is disengaged from the button 19 of the switch 26 to actuate the switch 26 so that the wire gripper jaws 30 are opened to release the wire W and the pneumatic motor 46 is operated to return the cradle 40 to its initial position. If the tensile strength of the crimped connection does not exceed the value predetermined by the load so that the wire gripper jaws 30 withdraw the wire W from the crimping ferrule 6 so that the Stop member 16 does not move the piston rod 24, the cradle 40 continues to rotate to its extreme clockwise position and thus actuates the switch 50, to break the circuit of the starting switch.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only.

I claim:

1. Apparatus for crimping an electrical connector onto the end of a wire and concomitantly testing the crimped connection between the wire and the connector comprising connector crimping means, an engageable and disengageable wire gripping means disposed adjacent to said connector crimping means, connector stop means disposed between said crimping means and said gripping means, said stop means permitting passage of said wire therethrough but not permitting passage of said connector, moving means for moving said gripping means relatively away from said crimping means, and a first control means responsive to said crimping means for engaging said gripping means with said wire concomitantly with crimping of said connector onto said wire and moving said gripping means relatively away from said crimping means, whereby, the crimped connector is pulled against said stop means and a second control means responsive to development of a predetermined tensile force in said wire for disengaging said gripping means form said wire whereby said crimped connection is subjected to a tensile test equal to said predetermined tensile force.

2. Apparatus as set forth in claim 1 wherein said wire gripping means comprises a pair of closeable gripping aws.

3. Apparatus as set forth in claim 1 including a third control means for rendering said crimping means inoperative, said third control means being actuated by said wire gripping means upon movement of said gripping means away from said crimping means in the event that said wire is pulled from said connector.

4. Apparatus as set forth in claim 1 including a lever pivoted intermediate its ends, said stop means being on one end of said lever, said second control means comprising force applying means and switch means disposed adjacent to the other end of said lever, said force applying means applying a test force opposed to said tensile force, said switch means being actuable when said tensile force overcomes said test force.

5. Apparatus for performing a crimping operation to form an electrical connection between an electrical connector and a wire and for testing the tensile strength of the electrical connection, the apparatus comprising connector crimping means for crimping the electrical connector onto the wire to form the electrical connection, means adjacent said crimping means for maintaining the electrical connector of the electrical connection in position thereat, wire-gripping means adjacent said crimping means for gripping the wire of the electrical connection, means for operating said wire-gripping means to move said wiregripping means with the wire being gripped by the wiregripping means away from said maintaining means there- 5 by subjecting the electrical connection to a tensile test equal to a predetermined tensile force, and means for disengaging said Wire-gripping means from the wire after the tensile test has been performed.

References Cited UNITED STATES PATENTS 2,544,522 3/1951 Bertelsen 29-407 6 2,809,546 10/1957 Broske 29-24352 2,827,941 3/ 1958 Stoltz. 3,329,002 7/1967 Schwalm 72416 THOMAS H. EAGER, Primary Examiner US. Cl. X.R. 

